The present invention relates to an air-conditioning system for a motor vehicle, by means of which individual air-conditioning zones of the vehicle interior can be supplied with separately temperature-controllable air. The present invention also relates to a method for controlling the temperature of a vehicle interior by means of this air conditioning system.
DE 197 39 578 A1 (corresponding to U.S. patent application Ser. No. 09/150,616, filed Sep. 10, 1998) discloses an air-conditioning system regulated on the air side. In this system, the space downstream of the heater, in which cold air guided past the heater can be mixed with warm air, is subdivided into four air mixing spaces located next to one another and separated by partitions. The partitions extend below the heater and likewise subdivide the cold-air bypass into four part ducts. By means of warm-air flaps arranged directly downstream of the heater and cold-air flaps for selectively closing the cold-air bypasses, an individual temperature can be set in each mixing space. This is accomplished irrespective of the temperatures in the other mixing spaces, by means of cold air being mixed with the warm air according to the desired ratio. During this so-called air-side temperature regulation, the hot engine coolant constantly flows through the heater. The individually temperature-controlled air of the individual air mixing spaces can be fed via air ducts to the corresponding air-conditioning zones of the vehicle.
The general problem of present day air-conditioning systems with their components, in particular the air valves or flaps, is basically that the construction space available for the air-conditioning system is very limited, and these systems therefore have to be constructed in an increasingly more compact form. Particularly those air-conditioning systems that are suitable for differently controlling the temperature of various air-conditioning zones, such as the system known from DE 197 39 578 A1, tend to require a larger construction space because of their larger number of structural parts. Furthermore, the regulation of the large number of flaps for setting the temperature in the four individual air mixing spaces, for the four interior zones, is highly complicated.
It is therefore one object of the present invention to provide an improved heating or air-conditioning system, by means of which individually temperature-controllable air can be provided for the different air-conditioning zones of the vehicle, which requires as small a construction space as possible and which allows simple regulation.
A further object of the invention is to provide an improved method for controlling the temperature of various interior zones of the motor vehicle.
In accomplishing these objects, there has been provided according to one aspect of the present invention a heating or air-conditioning system comprising: an evaporator for providing cold air; a heater located downstream of the evaporator for generating warm air heated by coolant from the motor vehicle engine, this heater having at least one partition dividing the air-conditioning system downstream of the evaporator into at least two regions arranged next to one another; a cold-air bypass duct guided past the heater in each of the regions; a regulator system for regulating the temperature of the coolant in the heater for bringing the entire heater to a predetermined temperature, whereby air flowing through the heater is controlled to a maximum temperature that is dependent on the temperature of the heater and that corresponds to an air temperature desired in a first interior zone of the vehicle; and an air control element in at least one of the bypass ducts for selectively bypassing cold air in at least one of the regions to lower the temperature of the air that is to be introduced into a second interior zone of the vehicle.
In accordance with another aspect of the present invention, there has been provided a method for independently controlling the temperature of a plurality of zones in a vehicle interior, by means of an air-conditioning system that includes a heater for exchanging heat with coolant from a vehicle engine, comprising: regulating the coolant throughflow through the heater to produce air exiting the heater at a first temperature corresponding to the highest temperature required in a first zone in the vehicle; supplying air at the first temperature to the first zone of the vehicle; and regulating the temperature of air provided to at least a second zone in the vehicle to a second temperature lower than the first temperature, by lowering the temperature of air exiting the heater at the first temperature by selectively admixing cooler air therewith.
Further objects, features and advantages of the present invention will become apparent from the detailed description of preferred embodiments of the invention that follows, when considered together with the accompanying figures of drawing.